UBC Theses and Dissertations
Three-dimensional nonlinear dynamic seismic behaviour of a seven story reinforced concrete building Doulatabadi, Peyman Rahmatian
The three-dimensional seismic dynamic behaviour of reinforced concrete buildings has not been studied as extensively as their planar behaviour. Experimental studies, although limited, demonstrate that there is significant interaction of torsional response with the response of a building along its two principal axes. In order to gain better understanding of this interaction, a recently developed computer program called CANNY - E was used in this study to evaluate the three-dimensional response of a reinforced concrete structure subjected to prescribe seismic excitations. The purpose of this research was to study the seismic behaviour of a well-instrumented seven story reinforced concrete building in Van Nuys, California. This building has been subjected to ground motions from several earthquakes since 1971 and sustained severe structural damage during the 1994 Northridge earthquake. The lateral force resistance of the building is provided by both interior column-slab and exterior column-spandrel beam frames. Typical floor plan dimensions are 19 by 49 meters. The behaviour of the building during three earthquakes having different levels of demand was investigated. The first strong ground excitation that the building experienced was in 1971, during the San Fernando earthquake. The 1987 Whittier and the 1994 Northridge earthquakes were the other two recorded ground excitations used in this study. Detailed time and frequency domain analyses of the recorded motions from these three earthquakes were conducted to determine the dynamic characteristics of the system at the beginning and during each event. Then, three-dimensional, linear and nonlinear dynamic time history analyses of the building were conducted for each earthquake. The results of this study showed that by performing a nonlinear analysis, even based on material properties obtained from the design specifications rather than on material properties determined from core samples, one can effectively predict the real response of a building during an earthquake. The state and sequence of damage could also be predicted.
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